Bench Lights

Well, they are mostly CCFL. Of course they have Royers in them and they gen erate EMI. I got an HP339a and to find its measurement flkoor of 0.0016% I had to connect the output to the input with wires as straight as possible. Using anything else it picked up too much noise, even with the filters on.

Then I am working on a scope and the trace is fat, I pull the arm light awa y and it flattens out. I turn off all the lights and I got the flatline I s hould.

So now I got a halogen in the arm lamp, which helps. I also still have the ability to shut of all the lights and have everything else still work. Even with the rest of the lights farther away it still has noticeable EMI.

The halogen is alright but it gets hot. that is inefficiency and not much t hough because it is like 50 watts. But it makes the shield on my arm lamp h ot and that is not only not nice now, any heat generation in the summer is no good here. We don't even use the oven. This is a BIG house and when that A/C comes on it is over a buck an hour to run the compressor.

I wonder now about LED lighting. I know it runs on a couple of volts, and i f they are downconverting it it is surely switched mode. Or is it ? They wo uld not just use a resistor, trying to be efficient.

If LED lighting does not emit much EMI I will consider changing to it. This place is bad enough with the bad wiring, yes I know I have to take care of that but still, that EMI is not what is coming form the light bulbs. But w hat is is up close and personal.

What y'all use for that ?

Reply to
jurb6006
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I use two of these style of lamp from Amazon for several months, one on each side. There are several different models. Works great and I don't notice any EMI issues. Some people bitchin' about reliability problems but hasn't happened to me yet.

I have a halogen gooseneck too but hardly need it

Reply to
bitrex

Dirty Electricity from LEDs The worst part is that I've found wide variations in EMI from commodity LED light bulbs. In the same box of bulbs, some are very noisy, while others are tolerably quiet. You may need to individually test the bulbs to find the best.

Kerosene or propane camping lantern. I actually did that at one company for lighting a screen room. However, I was soon ordered to remove them because they were a fire hazard. I though the "ambience" was rather nice, but I have to admit that it wouldn't have taken much to start a fire. I didn't try these, but I think Cyalume glow sticks might have worked: Yellow seems the brightest. You get about 12 hrs per stick at about $1.25/ea. I think 4 would be sufficient to light up a test bench. That's $5 per day for lighting, which is expensive but tolerable compared to the cost of LED lights, ferrite bead filtering, and possibly wire mesh shielding.

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Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
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Reply to
Jeff Liebermann

Hello, and I use a '70s era Tensor high-intensity lamp (also doubles as a piano lamp). It uses a 12-volt automotive bulb and has a high and low brightness switch. Oh, yeah, and no noise/EMI issues and plenty of light for close-in work. Sometimes older works better (except perhaps with people). Sincerely,

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J. B. Wood	            e-mail: arl_123234@hotmail.com
Reply to
J.B. Wood

enerate EMI. I got an HP339a and to find its measurement flkoor of 0.0016% I had to connect the output to the input with wires as straight as possible . Using anything else it picked up too much noise, even with the filters on .

way and it flattens out. I turn off all the lights and I got the flatline I should.

e ability to shut of all the lights and have everything else still work. Ev en with the rest of the lights farther away it still has noticeable EMI.

though because it is like 50 watts. But it makes the shield on my arm lamp hot and that is not only not nice now, any heat generation in the summer i s no good here. We don't even use the oven. This is a BIG house and when th at A/C comes on it is over a buck an hour to run the compressor.

if they are downconverting it it is surely switched mode. Or is it ? They would not just use a resistor, trying to be efficient.

is place is bad enough with the bad wiring, yes I know I have to take care of that but still, that EMI is not what is coming form the light bulbs. But what is is up close and personal.

LEDs, if run on dc, are as clean as it gets. Of course commercial lightbulb s all use switchers, not known for being EMI-free. Roll your own. Ebay has very cheap reject less power than claimed flat panel LEDs, or just rewire a lightbulb.

NT

Reply to
tabbypurr

They use capacitive droppers.

Reply to
Lucifer

The couple of LED lamps I have plugged into my Kill-a-Watt meter come up with power factors around either 0.6 (the cheapest ones) or 0.8 (a nicer Philips "dimmable" one), if that tells you anything.

I personally just use a couple of 4 foot "shop light" fluorescent fixtures over the bench, because they were cheap. :) I am not usually trying to do tiny-signal stuff, though.

If you do want to make "low noise" LED lighting, here are some ideas...

  1. Go to the big-box store and buy one of those LED "work lights" - the ones shaped like the old 300 W / 500 W halogen flood lights. Remove the existing power supply and drive it with a linear power supply at the right voltage. (Hopefully the power supply isn't potted/ impossibly entangled with the LEDs.) Work up an adapter from the "eye" / mounting holes on the back to one of your arm light brackets.
  2. Roll-your-own with LEDs and some perf board, or ready-made boards from somebody like
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    . Clive made his boards before you could even get ready-made LED lamps at retail. They are designed for strings of R, G, and B LEDs, but you could also just buy white LEDs and install them. If you end up needing less light, just don't populate the whole board.
  3. Go to the car parts store and buy some LED lamps that are designed to replace regular 12 V lamps in vehicles. I think pretty much all of these just use resistors in series with the 12 V. You also get to figure out a socket, reflector, etc (or use one off of a car).
  4. Get some of the LED modules that are designed to go in signs for buildings, as a replacement for neon tubes. Sometimes gas stations also use them bare around their front windows. These usually run on 12 V and each one has 3 LEDs and a resistor in it. They come on a string with a few inches of wire between each module; stick several modules parallel to each other on a metal plate and that's a lamp. Examples here:
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  5. Buy some of the LEDs that come assembled on a flexible strip or tape. You can cut the tape every 3 or so LEDs (it's marked) to get whatever length you want. Stick some of this to a plate, or wind it around a piece of pipe, to make a lamp. Some examples at the link above, plus these are all over Ebay, Amazon, etc.

If you want a bunch of them in a small area, these are IMHO a little harder to use than the sign modules, because you either need to fold/wind up the strip, or cut it in several places and solder a lot of jumpers. The sign modules come with the jumpers already installed.

Standard disclaimers apply: I don't get money or other consideration from any companies mentioned.

Matt Roberds

Reply to
mroberds

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